README: fix indentation of Go code block (#147)
README: fix indentation of Go code block (#147)

Signed-off-by: Tal Nordan <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@talnordan.com>
istio/go-control-plane,envoyproxy/go-control-plane,envoyproxy/go-control-plane,istio/go-control-plane